Biologia de La Polinizacion en Paltos
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Transcript of Biologia de La Polinizacion en Paltos
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Gad Ish-Am (September 2004) 1
Biologa de la Polinizacin
Gad Ish - Am
Avocado Pollination Basics
Gad Ish-AmAgricultural R & D
Western Galilee, IsraelOhalo College, P.O.B. 222
Katzrin, 12900, Israel
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Gad Ish-Am (September 2004) 2
To maximize yield one needs:
Sufficient cross pollination
Effective pollination
Efficient pollinator(many honey bees)
Pollinizers in close proximity
Female Phase FlowerReed
Male Phase FlowerFuerte
Avocado Flower Phases
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Gad Ish-Am (September 2004) 3
The avocado flower
Female Phase
Male Phase
Ettinger pollen grains attachedTo an open valve of the anther Fuerte pollen grain
Source: Gazit & Degani, 2002.Source: Ish-Am, 1994. PhD Thesis
The avocado pollen
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Gad Ish-Am (September 2004) 4
Pollination Terms:
Pollination the transfer of pollen from the anther to the stigma. Cross pollination the pollen deposited on
the stigma is from another cultivar. Close pollination the pollen deposited on
the stigma is from another flower of the same tree or cultivar.
Self pollination the pollen deposited on the stigma is from the same flower.
Pollination Terms:
Pollinator: The agent which transfers pollen from the male to the female floral organ.
Pollinated Tree: A cultivar that receives the pollen (i.e. Hass).
Pollinizer: A cultivar that donates pollen to another cultivar.Common Hass pollinizers: Bacon, Zutano, Ettinger, Edranol, Walter Hole.
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Gad Ish-Am (September 2004) 5
Pollination Terms:Fertilization the fusion of the male
gamete with the female gamete forming the zygote.
Effective Pollination pollination which leads to fertilization.
Non effective pollination pollination which does NOT lead to fertilization.
Avocado Flowering Sequence
Type A
Type B
Female flowersMale flowers before dehiscenceMale dehiscing flowers
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Gad Ish-Am (September 2004) 6
Within the tree overlapping of Hass female and male flowers
Female-phase flowerFrom the morning
Noontime Male-phase flower
Avocado flower pollination routes
Type A
Type B
1. Cross pollination
1.1.
2. Close pollination
2.
2.
3. Self pollination3.
3.
Female flowersMale flowers before dehiscenceMale dehiscing flowers
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Gad Ish-Am (September 2004) 7
Getting the pollen to the
flower
Regions of avocado pollen transferon the honeybee body
Avocado pollen
Brassicaceae pollen
Forehead, between antennas
Ventral head
Ventral thoraxLegs
Posterior of ventral abdomen
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Gad Ish-Am (September 2004) 8
Honey bees transferring avocado pollen between male and female flowers
Why does the avocado tree produce so many flowers?
Attraction: the whole tree acts like a giant inflorescence with many small flowers.
Small fertilization percent: thus most flowers do not set fruit.
Competition: between fruits and growth, as well as among the fruits, which leads to high rate of primary-fruit abscission.
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Gad Ish-Am (September 2004) 9
Hand pollinated Hass stigmas by Ettingerpollen. Four hrs of germination.
Shoval, 1987
1-4 pollen grains
>20 pollen grains
5-19 pollen grains
Percent of pistil length
Perc
ent
of f
lowe
rs
Pollen tubesReach:
Avocado Pollen Germination Rate
Effect of competitionbetween and cooperationamong the pollen grains
The need for honeybees: pollination rate
Source: Ish-Am, 1994. PhD Thesis
PollinizerNear Far Near Farl-close-l---cross---l l-close-l--cross--l
Arguments:a. Number of bees
per tree: more than 20 are demanded.
d. Cultivar flowering-type: A types get higher close-pollination.
b. Pollination type:close-pollination is higher than cross-pollination, with a far pollinizer.
c. Pollinizer distance:near pollinizer induces higher cross-pollination.
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Gad Ish-Am (September 2004) 10
The need for honeybees: number of pollen grains per stigma
Arguments:a. Number of bees
per tree: more than 20 are demanded.
Source: Ish-Am, 1994. PhD Thesis
Near Far Near Far Pollinizerl-close-l---cross---l l-close-l--cross--l
d. Cultivar flowering-type: A types gets more close-pollen grains.
c. Pollinizer distance:near pollinizer causes more cross-pollen grains.
b. Pollination type:close-pollination develops more pollen grains.
Hass yields decrease significantlywith increasing distance from Ettinger
Source: Guil et al. 1986. Alon Hanotea 40:443-455
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Gad Ish-Am (September 2004) 11
Survival of cross vs. self progenies
Source: Degani, Goldring and Gazit. 1989. J. Amer. Soc. Hort. Sci. 114:106-111 Via www.avocadosource.com
Percent of crossed Hassfruits by both Ettinger or Fuerteaccording to time after fruit set.
0102030405060708090
May 5 Sept 10 Oct 22
Sampling Date
% o
ut-c
ross
ing
Source: Degani et al. 1990. HortScience 25(4):471-473 via www.avocadosource.com
200
210
220
230
240
250
260
270
Teague Pollination Block Topa Topa Pollination Block
Frui
t Wei
ght (
g)
Teague or Topa Topa Ettinger Fuerte (selfed)
0
10
20
30
40
50
60
Teague Pollination Block Topa Topa Pollination Block
See
d W
eigh
t (g)
Teague or Topa Topa Ettinger Fuerte (selfed)
Pollen Donor
Pollen Donor
ab
c
a
b
b
bc
a a a
a
Fuerte Seed Weight
Fuerte Fruit Weight
The pollen donor cultivar impacts fruit weight and seed size.
Data from Israel for Fuerte fruit with Teague, Ettinger or Topa Topa as pollen donors.
Pollen Donor Effect
(metaxenia)
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Gad Ish-Am (September 2004) 12
PROXIMITY
Percentage of cross-pollen carrying honeybees on Hass
as a function of distance from the pollinizer
Source: Ish-Am and Eisikowitch, 1996.
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Gad Ish-Am (September 2004) 13
Hass cross pollination rate as a function of bee density and distance from the pollinizer
Source: Ish-Am, 1994. PhD Thesis
Close Ettinger
Far Ettinger
Multiple pollinizers
Bacon + Ettinger + Zutano
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Gad Ish-Am (September 2004) 14
ATTRACTIVITY
Hass flowering, honeybee activity and fruit set - Israel, spring 1992
Source: Ish-Am, 1994. PhD Thesis
No correlationfound between avocado flowering intensity and honeybee activity in the presence of competing bloom.High correlationfound between fruit set and honeybee activity.
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Gad Ish-Am (September 2004) 15
Pollen load on hind leg of a honeybee containing Ettinger pollen.
Pollen load on hind leg of a honeybee containing White Mustard pollen.
Source: Ish-Am, 1994. PhD Thesis
Avocado pollen is not organized well in the honeybees pollen-load
Close-up of Ettinger pollen in the pollen load of a honeybee
Close-up of White Mustard pollen in the pollen load of a honeybee
Source: Ish-Am, 1994. PhD Thesis
Close-up of pollen in the honeybees pollen load
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Gad Ish-Am (September 2004) 16
How many honeybees per tree
are necessary?
How many honeybee hives per hectare
are needed?
Monitoring honeybee-hive density
Source: Ish-Am, 1994. PhD Thesis
Bees per tree
Self-fruit set
Cross-fruit set
Addinghives
0 none none necessary
1 - 4 none none necessary
5 - 9 few none necessary
10 - 25 many few on the1st row
recommended
26 - 55 many on 1st to2nd rows
may be helpful
more than 55
many up to the4st row
not needed
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Gad Ish-Am (September 2004) 17
To maximize yield one needs:
Sufficient cross pollination
Effective pollination
Efficient pollinator(many honey bees)
Pollinizers in close proximity
For more information visit
www.avocadosource.com
For more information visit
www.avocadosource.com